Side-firing fiber delivery device with active cooling cap

ABSTRACT

An optical fiber includes an internal fiber, an end surface, a first cap member and a second cap member. The internal fiber terminates at a fiber tip. The end surface transmits laser energy delivered through the internal fiber. The first cap member extends over the end surface and includes a first end on a first side of the end surface and a second end on a second side of the end surface. The second cap member extends over the first cap member and includes a first end on the first side of the end surface and a second end on the second side of the end surface, the second end of the second cap member is attached to the second end of the first cap member.

PRIORITY CLAIM

The present application is a continuation of U.S. patent applicationSer. No. 12/185,592, filed Aug. 4, 2008 and issued Oct. 14, 2014 as U.S.Pat. No. 8,858,542, which is based on and claims the benefit of U.S.provisional patent application Ser. No. 60/953,721, filed Aug. 3, 2007.The above-referenced applications are hereby incorporated by referencein their entirety.

FIELD OF THE INVENTION

This invention relates to the field of medical lasers utilizing opticalfibers. More specifically, the present invention relates to aside-firing optical fiber utilizing internal and external coolingstreams to prevent premature failure at a fiber tip.

BACKGROUND OF THE INVENTION

Medical lasers have been used in treatment procedures involving variouspractice areas, including, for example, urology, neurology,otorhinolaryngology, general anesthetic ophthalmology, dentistry,gastroenterology, cardiology, gynecology, and thoracic and orthopedicprocedures. Generally, these procedures require precisely controlleddelivery of laser energy, and often the area to which the laser energyis to be delivered is located deep within the body; for example, at theprostate or at the fallopian tubes. Due to the location of the targettissue deep within the body, the medical procedure requires that theoptical fiber be flexible and maneuverable. Various light sources can beused with optical fiber devices dependent upon the requirements for thelight source; for example, pulsed lasers, diode lasers and neodymiumlasers can be used as light sources. Representative lasers used inmedical treatment procedures include Ho:YAG lasers and Nd:YAG lasers.

In medical procedures utilizing laser energy, the laser is coupled to anoptical fiber adapted to direct laser radiation from the laser, throughthe fiber and to the treatment area. Typically, a surgical probe isutilized in the treatment of body tissue with laser energy. The surgicalprobe generally includes an optical fiber coupled to a laser source, andthe probe tip is positioned on the optical fiber opposite the lasersource, such that the tip of the probe can be positioned adjacent to thetargeted tissue. Laser energy is directed out of the probe tip of theoptical fiber onto desired portions of the targeted tissue.

Depending upon the operational conditions during laser treatment, a capon the surgical probe can overheat. Overheating of the cap can lead tofailure of the optical fiber. If the optical fiber fails, the lasersystem fails. Overheating of the cap can cause the cap to burn, detach,or even shatter during treatment inside the patient, which can lead toinjury to the patient.

SUMMARY OF THE INVENTION

Some embodiments of the invention are directed to optical fibers andmedical laser systems that may be used to deliver laser energy forperforming a medical procedure. In some embodiments, an optical fiberincludes an internal fiber, an end surface, a first cap member and asecond cap member. The internal fiber terminates at a fiber tip. The endsurface transmits laser energy delivered through the internal fiber. Thefirst cap member extends over the end surface and includes a first endon a first side of the end surface and a second end on a second side ofthe end surface. The second cap member extends over the first cap memberand includes a first end on the first side of the end surface and asecond end on the second side of the end surface, the second end of thesecond cap member is attached to the second end of the first cap member.

In some embodiments, an optical fiber includes an internal fiber thatterminates at a fiber tip. A reflective surface reflects laser energytransmitted through the internal fiber. An inner cap member extends overthe reflective surface. An outer cap member extends over the inner capmember and includes an exterior surface having a side-firing portthrough which laser energy transmitted through the internal fiber andreflected by the reflective surface is discharged.

In some embodiments, an optical fiber includes an internal fiber thatterminates at a fiber tip and A reflective surface reflects laser energytransmitted through the internal fiber. The optical fiber also includesa tip cap assembly comprising an inner cap member, an outer cap member,and a cap irrigation channel. The inner cap member extends over thereflective surface and includes a proximal end on a proximal side of thereflective surface and a distal end on a distal side of the reflectivesurface. The outer cap member extends over the inner cap member andincludes (i) a distal end on the distal side of the reflective surface,the distal end of the outer cap member being attached to the distal endof the inner cap member, and (ii) an exterior surface having a portthrough which laser energy transmitted through the internal fiber andreflected by the reflective surface is discharged. The cap irrigationchannel is between the inner cap member and the outer cap member.

Some embodiments of the medical laser system include a laser unit forgenerating laser treatment energy, and an optical fiber attached to thelaser unit for delivering the laser treatment energy to a treatmentlocation. In some embodiments, the optical fiber includes an internalfiber terminating at a fiber tip, a reflective surface that reflectslaser energy transmitted through the internal fiber, and a tip capassembly. In some embodiments, the tip cap assembly includes an innercap member, an outer cap member and a cap irrigation channel between theinner cap member and the outer cap member. The inner cap member extendsover the reflective surface. The outer cap member extends over the innercap member and includes an exterior surface having a side-firing portthrough which laser energy transmitted through the internal fiber andreflected by the reflective surface is discharged.

The above summary of the various representative embodiments of theinvention is not intended to describe each illustrated embodiment orevery implementation of the invention. Rather, the embodiments arechosen and described so that others skilled in the art may appreciateand understand the principles and practices of the invention. Thefigures in the detailed description that follows more particularlyexemplify these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

These as well as other objects and advantages of this invention, will bemore completely understood and appreciated by referring to the followingmore detailed description of the presently preferred exemplaryembodiments of the invention in conjunction with the accompanyingdrawings of which:

FIG. 1 is a block diagram illustration of a laser system according to anembodiment of the present invention.

FIG. 2 is a perspective end view of an optical fiber according to anembodiment of the present invention.

FIG. 3 is a section view of the optical fiber of FIG. 2.

FIG. 4 is a section view of the optical fiber of FIG. 2 being introducedto a treatment location with a cystoscope according to an embodiment ofthe present invention.

FIG. 5 is a graph comparing percentage of transmission of an opticalfiber (2090 fiber) to an optical fiber with the active cooling cap ofthe present invention.

While the invention is amenable to various modifications and alternativeforms, specifics thereof have been shown by way of example in thedrawings and will be described in detail. It should be understood,however, that the intention is not to limit the invention to theparticular embodiments described. On the contrary, the intention is tocover all modifications, equivalents, and alternatives.

DETAILED DESCRIPTION OF THE DRAWINGS

The present invention comprises an optical fiber for use with a medicallaser system that utilizes internal and external cooling streams andrelated methods of monitoring an optical fiber to determine if anoptical fiber cap on the optical fiber is in imminent danger of capfailure. The laser system includes a photodetector for convertingreturned light from the optical fiber cap to an electronic signal forcomparison to a trigger threshold value known to be indicative ofimminent fiber cap failure. The returned light can be the main lasertreatment wavelength, an auxiliary wavelength, such as an aiming beam,or infrared wavelengths generated by a temperature of the optical fibercap. In the event the electronic signal reaches the trigger thresholdvalue, the laser system can be temporarily shut-off or the power outputcan be reduced. In one preferred embodiment, the present invention canbe utilized as part of a Greenlight HPS system manufactured by AmericanMedical Systems of Minnetonka, Minn. and as described in U.S. Pat. Nos.6,554,824 and 6,986,764, which are herein incorporated by reference.

Referring to FIG. 1, there is depicted a block diagram showing anexemplary laser system 100, which may be employed for implementing thepresent invention. Laser system 100 includes a solid-state laser unit102, which is used to generate laser light for delivery through opticalfiber 106 to target tissue 104. Laser unit 102 is capable of beingoperated in a pulsed mode or continuous wave.

Laser unit 102 more specifically comprises a laser element assembly 110,pump source 112, and frequency doubling crystal 122. In the preferredembodiment, laser element assembly 110 outputs 1064 nm of light, whichis focused into frequency doubling crystal 122 to create 532 nm oflight. According to one implementation, laser element assembly 110 maybe a neodymium doped YAG (Nd:YAG) crystal, which emits light having awavelength of 1064 nm (infrared light) when excited by pump source 112.Laser element assembly 110 may, alternatively, be fabricated from anysuitable material, wherein transition and lanthanide metal ions aredisposed within a crystalline host (such as YAG, Lithium YttriumFluoride, Sapphire, Alexandrite, Spinel, Yttrium Orthoaluminate,Potassium Gadolinium Tungstate, Yttrium Orthovandate, or LanthahumScandium Borate). Laser element assembly 110 is positioned proximal topump source 112, and may be arranged in parallel relation therewith,although other geometries and configurations may be employed.

Pump source 112 may be any device or apparatus operable to excite laserelement assembly 110. Non-limiting examples of devices which may be usedas pump source 112 include: arc lamps, flashlamps, and laser diodes.

A Q-switch 114 disposed within laser unit 102 may be operated in arepetitive mode to cause a train of micropulses to be generated by laserunit 102. Typically the micropulses are less than 1 microsecond induration separated by about 40 microseconds, creating a quasi-continuouswave train. Q-switch 114 is preferably of the acousto-optic type, butmay, alternatively, comprise a mechanical device such as a rotatingprism or aperture, an electro-optical device, or a saturable absorber.

Laser unit 102 is provided with a control system 116 for controlling andoperating laser unit 102. Control system 116 will typically include acontrol processor which receives input from user controls (including butnot limited to a beam on/off control, a beam power control, and a pulseduration control), and processes the input to accordingly generateoutput signals for adjusting characteristics of the output beam to matchthe user inputted values or conditions. With respect to pulse durationadjustment, control system 116 applies an output signal to a powersupply (not shown) driving pump source 112 which modulates the energysupplied thereto, in turn, controlling the pulse duration of the outputbeam. Laser unit 102 further includes an output port 118 couplable to aproximal end 119 of optical fiber 106. Output port 118 directs the lightgenerated by laser unit 102 into optical fiber 106 for delivery totissue 104.

Although FIG. 1 shows an internal frequency doubled laser, it is only byway of example. The infrared light can be internally or externallyfrequency doubled using non-linear crystals such as KTP, LithiumTriborate (LBO), or Beta Barium Borate (BBO) to produce 532 nm of light.The frequency doubled, shorter wavelength light is better absorbed bythe hemoglobin and char tissue, and promotes more efficient tissueablation.

Referring now to FIGS. 2 and 3, optical fiber 200 of the presentinvention generally comprises an internal fiber 202 defining a fiber tip204 at a treatment end 205 of the optical fiber 200. Internal fiber 202is manufactured from a silicon material, typical of optical fibers.Internal fiber 202 is protected from damage prior to use and duringintroduction to the treatment location with a protective jacket assembly206. Projective jacket assembly 206 generally comprises a body tubeassembly 208 and a tip cap assembly 210. Body tube assembly 208generally protects a majority portion of the internal fiber 202,extending from proximal end 119 to the tip cap assembly 210. Body tubeassembly 208 generally comprises an internal fiber jacket 212, and anexternal body tube 214 with a body tube channel 216 definedtherebetween. Similar to internal fiber 202, internal fiber jacket 212and external body tube 214 are constructed of a suitable siliconmaterial.

As illustrated in FIG. 3, tip cap assembly 210 generally comprises aninner cap member 218, and an outer cap member 220 defining a capirrigation channel 222 therebetween. Together, cap irrigation channel222 and body tube channel 216 cooperatively define an internalirrigation channel 224. Outer cap member 220 includes a side port 226positioned within an exterior surface 228. Side port 226 generallydefines a radiused edge 230, such that laser energy can be directed fromthe fiber tip 204 to the treatment location.

In operation, optical fiber 200 and, more specifically, fiber tip 204,can be introduced to the treatment location utilizing a conventionalcystoscope 240, as shown in FIG. 4. Generally, the cystoscope 240 isadvanced through the urethra and proximate the treatment area. Once thecystoscope 240 is positioned at the treatment area, an irrigant such aswater or saline can be injected through the cystoscope 240. Whenperforming a medical laser procedure with the laser system 100, opticalfiber 200 is advanced through the cystoscope 240 such that side port 226is positioned proximate the desired treatment location.

With the side port 226 oriented toward the treatment location, saline issimultaneously directed through the internal irrigation channel 224, andin an external irrigation channel 242 defined between the cystoscope 240and the protective jacket assembly 206. With an external cooling stream244 flowing across exterior surface 228, and an internal cooling stream246 flowing between the outer cap member 220 and the inner cap member218, control system 116 directs laser energy through the optical fiber200 such that a treatment beam exits the fiber tip 204 and out the sideport 226. As the treatment beam contacts the treatment location, heat isgenerated at a tissue surface as the laser energy ablates the targetedtissue. The dual simultaneous cooling of the external cooling stream 244and the internal cooling stream 246 remove heat energy from the fibertip 204. As fiber tip 204 is prevented from overheating, ablated tissueis kept from adhering within or around the side port 226, or to theexterior surface 228. In addition, the outer cap member 220 provides agap between the fiber tip 204 and the treatment location, such thattissue does not attach to the fiber tip 204 due to localized heating atthe fiber tip 204. With heat energy removed at the tip cap assembly 210,overheating is avoided such that devitrification and cratering ofoptical fiber 200 does not occur.

FIG. 5 provides a comparison between the standard 2090 fiber that istypically used with a GreenLight HPS laser treatment device fortreatment of benign prostate hyperplasia (BPH) and the fiber with theactive cooling cap of the present invention. As shown, the percentage oftransmission of light stays steady in the fiber with the active coolingcap, while the 2090 fiber experiences intermittent decreases intransmission of light as energy is increased. As indicated by the graph,the active cooling cap fiber of the present invention provides reducedlaser energy absorption by preventing the tissue contact at the laserfiring point and the areas adjacent to the firing point; the tissue isin contact with the outer cap rather than the inner cap through whichthe laser light is being delivered. Further, the irrigation fluid fromthe inner cap pushes the tissue debris out of the firing point of theinner cap and, hence, further prevents tissue debris from depositing andburning at the firing point. Moreover, the active cooling cap of thepresent invention can provide cooling from inside of the cap even whenthe irrigation fluid from the cystoscope is totally blocked by tissue.

Although specific examples have been illustrated and described herein,it will be appreciated by those of ordinary skill in the art that anyarrangement calculated to achieve the same purpose could be substitutedfor the specific examples shown. This application is intended to coveradaptations or variations of the present subject matter. Therefore, itis intended that the invention be defined by the attached claims andtheir legal equivalents.

We claim:
 1. An optical fiber comprising: an internal fiber terminatingat a fiber tip; an end surface that reflectively transmits laser energydelivered through the internal fiber; a first cap member extending overthe end surface; a second cap member extending over the first cap memberthe second cap member being attached to a distal end of the first capmember and having a port through which laser energy is transmitted; anda cap irrigation channel between the first cap member and the second capmember.
 2. The optical fiber of claim 1, further comprising a body tubeassembly surrounding a portion of the internal fiber, the body tubeassembly including an internal fiber jacket, an external body tube, anda body tube channel between the internal body tube and the external bodytube, wherein the cap irrigation channel and the body tube channelcooperatively define an internal irrigation channel.
 3. The opticalfiber of claim 2, wherein the body tube assembly, first cap member,second cap member and cap irrigation channel are adapted forintroduction through a lumen of a device, whereupon an internal fluidflow can be directed through the internal irrigation channel and anexternal fluid flow can be directed through an external irrigationchannel defined between an interior surface of the lumen, an exteriorsurface of the body tube assembly, and an exterior surface of the secondcap member.
 4. The optical fiber of claim 1, wherein laser energydelivered through the internal fiber and transmitted from the endsurface is transmitted through the first cap member.
 5. The opticalfiber of claim 1, wherein the second cap member provides a physicalbarrier preventing contact between the fiber tip and the treatmentlocation during a treatment procedure.
 6. An optical fiber comprising:an internal fiber terminating at a fiber tip; a reflective surface thatreflects laser energy transmitted through the internal fiber; an innercap member extending over the reflective surface; an outer cap memberextending over the inner cap member, the outer cap member being attachedto a distal end of the inner cap member and including an exteriorsurface having a side-firing port through which laser energy transmittedthrough the internal fiber and reflected by the reflective surface isdischarged; and a cap irrigation channel between the inner cap memberand the outer cap member.
 7. The optical fiber of claim 6, furthercomprising a body tube assembly surrounding a portion of the internalfiber, the body tube assembly including an internal fiber jacket, anexternal body tube, and a body tube channel between the internal bodytube and the external body tube, wherein the cap irrigation channel andthe body tube channel cooperatively define an internal irrigationchannel.
 8. The optical fiber of claim 7, wherein the body tubeassembly, inner cap member, outer cap member and cap irrigation channelare adapted for introduction through a lumen of a device, whereupon aninternal fluid flow can be directed through the internal irrigationchannel and an external fluid flow can be directed an externalirrigation channel defined between an interior surface of the lumen, anexterior surface of the body tube assembly, and an exterior surface ofthe outer cap member.
 9. The optical fiber of claim 6, wherein the outercap member provides a physical barrier preventing contact between thefiber tip and a treatment location during a treatment procedure.
 10. Anoptical fiber comprising: an internal fiber terminating at a fiber tip;a reflective surface that reflects laser energy transmitted through theinternal fiber; and a tip cap assembly comprising: an inner cap memberextending over the reflective surface and including a proximal end on aproximal side of the reflective surface and a distal end on a distalside of the reflective surface; an outer cap member extending over theinner cap member and including (i) a distal end on the distal side ofthe reflective surface, the distal end of the outer cap member beingattached to the distal end of the inner cap member and (ii) an exteriorsurface having a port through which laser energy transmitted through theinternal fiber and reflected by the reflective surface is discharged;and a cap irrigation channel between the inner cap member and the outercap member.
 11. The optical fiber of claim 10, further comprising a bodytube assembly surrounding a portion of the internal fiber and includingan internal fiber jacket, an external body tube, and a body tube channelbetween the internal body tube and the external body tube, wherein thecap irrigation channel and the body tube channel cooperatively define aninternal irrigation channel.
 12. The optical fiber of claim 11, whereinthe body tube assembly and the tip cap assembly are adapted forintroduction through a lumen of a device, whereupon an internal fluidflow can be directed through the internal irrigation channel and anexternal fluid flow can be directed through an external irrigationchannel defined between an interior surface of the lumen, an exteriorsurface of the body tube assembly, and an exterior surface of the outercap member.
 13. The optical fiber of claim 10, wherein the outer capmember provides a physical barrier preventing contact between the fibertip and a treatment location during a treatment procedure.
 14. Theoptical fiber of claim 10, wherein the cap irrigational channel isconfigured to direct a fluid distally out of the tip cap assembly. 15.The optical fiber of claim 14, wherein the inner and outer cap membersextend along a first axis and the port is opposite of the reflectivesurface along a second axis transverse with the first axis.
 16. Theoptical fiber of claim 15, further comprising a fluid exit portconfigured to direct the fluid distally along the first axis.
 17. Theoptical fiber of claim 16, wherein the fluid exit port includes anannular opening coaxial with the first axis.
 18. A medical laser systemcomprising: a laser unit for generating laser treatment energy; and anoptical fiber attached to the laser unit for delivering the lasertreatment energy to a treatment location, the optical fiber comprising:an internal fiber terminating at a fiber tip and including a reflectivesurface that reflects laser energy transmitted through the internalfiber; and a tip cap assembly comprising: an inner cap member extendingover the reflective surface; an outer cap member extending over theinner cap member and being attached to a distal end of the inner capmember, the outer cap member including an exterior surface having aside-firing port through which laser energy transmitted through theinternal fiber and reflected by the reflective surface is discharged;and a cap irrigation channel between the inner cap member and the outercap member.
 19. The medical laser system of claim 18, furthercomprising: a device for accessing a treatment site within a patient'sbody, the device having a lumen extending therethrough, the opticalfiber being adapted for insertion through the lumen such that anexternal fluid flow can be directed between an interior surface of thelumen and an external surface the optical fiber.
 20. The medical lasersystem of claim 19, wherein the device is a cystoscope.